Objective : Several medicinal plants have been evaluated for their antidiarrhoeal activity. Most studies evaluated their effect on intestinal motility and antimicrobial activity and, therefore, did not take into account the pathogenesis of infectious diarrhoea. Features of infectious diarrhoea like abdominal pain, cramps, inflammation, and passage of blood/mucus in the stools are the combined effect of one or more virulence factors of the infecting organism. The effect of medicinal plants on the microbial virulent features can serve as marker(s) for testing their efficacy. In this study, we evaluated the effect of a decoction of dried leaves of
Dalbergia sissoo
on aspects of pathogenicity, that is, colonisation to intestinal epithelial cells and production/action of enterotoxins. This was done to define its possible mechanism(s) of action in infectious diarrhoea.
Materials and Methods : Antibacterial, antiprotozoal, and antiviral activities of the plant decoction were checked by agar dilution method, tube dilution method, and neutral red uptake assay, respectively. Cholera toxin (CT) and
Escherichia coli
labile toxin (LT) were assayed by ganglioside monosialic acid receptor ELISA. Suckling mouse assay was used to assess
E. coli stable toxin (ST). As a measure of colonisation, the effect against adherence of
E. coli and invasion of
E. coli and
Shigella flexneri
to HEp-2 cells were studied.
Results: The decoction had no antibacterial, antiprotozoal, and antiviral activity. It reduced the production and the binding of CT and bacterial adherence and invasion.
Conclusion : This study showed that
D .
sissoo is antidiarrhoeal as it affects bacterial virulence. However, it has no antimicrobial activity.
